I don't see the connection. The Pan-Arab movement was largely secular and in most of it's manifestations (the Baath in Syria and Iraq, Nasser in Egypt) cracked down hard on fundamentalist/extremist groups viewing them as both backwards and a threat (one of the ironies of the Pan-Arab movement, which began in part to present a united front against Western Powers and Israel specifically, is how focused it was on Westernizing their countries at the same time).
Maybe you mean it "animated the modern terrorist movement" in the sense that it rose in opposition to Pan-Arabism? I think that's a stretch but much less so then the above.